The invention relates to an apparatus for the sterilization of gaseous media, for example air, in which germs such as bacteria and the like are contained, having at least one housing frame, at least one layer having a labyrinth-like structure pervious to the medium held in the frame and at least one UV-source arranged to act upon the layer.
Such devices are installed in hospitals, medical treatment rooms and in part also in industrial locations, in order to create in the rooms in question an environmental condition which is as germ-free as possible. Conventional sterilization devices are in use, the essential component of which is a filter of a germ-impervious material, so that the germs contained in the medium are retained, but nevertheless they are not killed. There is thus a risk of penetration through the germ-proof filter material because of the continuous formation of new germs, so that such filters must be frequently replaced. During the replacement operation and also during use of the apparatus, it is therefore not possible to preclude the entry of germs into the area which is intended to be kept germ-free.
From German Offenlegungsschrift No. 2243223, it is also known to locate upstream of such a filter one or more UV-sources which have the purpose of killing the collected germs and thus preventing them from penetrating through the filter. Because of the filter materials conventionally used, the UV-radiation can effect its germ-killing action substantially only on the free filter surface, whereas it is prevented from entering inside the filter by absorption of the radiation. Because of the relatively short time during which the germs are subjected to the UV-radiation at the filter surface, it is impossible to avoid not only dead but also still living germs from passing inside the filter. During the time of use, a radiation-absorbing layer of collected germs and other retained particles forms on the free filter surface, so that the germ-killing effect of the UV-radiation at the filter surface becomes lost more or less rapidly. Like the abovementioned filters, therefore, even with the provision of UV-radiation, frequent replacement of filters, due to the disadvantages connected with the presence of living germs, is absolutely essential.